<?php
/**
 * Zend Framework
 * LICENSE
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 * @category Zend
 * @package Zend_Filter
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license http://framework.zend.com/license/new-bsd New BSD License
 * @version $Id: Null.php 24593 2012-01-05 20:35:02Z matthew $
 */
/**
 *
 * @see Zend_Filter_Interface
 */
require_once 'Zend/Filter/Interface.php';

/**
 *
 * @category Zend
 * @package Zend_Filter
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license http://framework.zend.com/license/new-bsd New BSD License
 */
class Zend_Filter_Null implements Zend_Filter_Interface {

    const BOOLEAN = 1;

    const INTEGER = 2;

    const EMPTY_ARRAY = 4;

    const STRING = 8;

    const ZERO = 16;

    const ALL = 31;

    protected $_constants = array(self::BOOLEAN => 'boolean', self::INTEGER => 'integer', self::EMPTY_ARRAY => 'array', self::STRING => 'string', self::ZERO => 'zero', self::ALL => 'all');

    /**
     * Internal type to detect
     * @var integer
     */
    protected $_type = self::ALL;

    /**
     * Constructor
     * @param string|array|Zend_Config $options OPTIONAL
     */
    public function __construct ($options = null) {
        if ($options instanceof Zend_Config) {
            $options = $options -> toArray ();
        } else 
            if ( ! is_array ($options)) {
                $options = func_get_args ();
                $temp = array();
                if ( ! empty ($options)) {
                    $temp = array_shift ($options);
                }
                $options = $temp;
            } else 
                if (is_array ($options) && array_key_exists ('type', $options)) {
                    $options = $options['type'];
                }
        if ( ! empty ($options)) {
            $this -> setType ($options);
        }
    }

    /**
     * Returns the set null types
     * @return array
     */
    public function getType () {
        return $this -> _type;
    }

    /**
     * Set the null types
     * @param integer|array $type
     * @throws Zend_Filter_Exception
     * @return Zend_Filter_Null
     */
    public function setType ($type = null) {
        if (is_array ($type)) {
            $detected = 0;
            foreach ($type as $value) {
                if (is_int ($value)) {
                    $detected += $value;
                } else 
                    if (in_array ($value, $this -> _constants)) {
                        $detected += array_search ($value, $this -> _constants);
                    }
            }
            $type = $detected;
        } else 
            if (is_string ($type)) {
                if (in_array ($type, $this -> _constants)) {
                    $type = array_search ($type, $this -> _constants);
                }
            }
        if ( ! is_int ($type) || ($type < 0) || ($type > self::ALL)) {
            require_once 'Zend/Filter/Exception.php';
            throw new Zend_Filter_Exception ('Unknown type');
        }
        $this -> _type = $type;
        return $this;
    }

    /**
     * Defined by Zend_Filter_Interface
     * Returns null representation of $value, if value is empty and matches
     * types that should be considered null.
     * @param string $value
     * @return string
     */
    public function filter ($value) {
        $type = $this -> getType ();
        // STRING ZERO ('0')
        if ($type >= self::ZERO) {
            $type -= self::ZERO;
            if (is_string ($value) && ($value == '0')) {
                return null;
            }
        }
        // STRING ('')
        if ($type >= self::STRING) {
            $type -= self::STRING;
            if (is_string ($value) && ($value == '')) {
                return null;
            }
        }
        // EMPTY_ARRAY (array())
        if ($type >= self::EMPTY_ARRAY) {
            $type -= self::EMPTY_ARRAY;
            if (is_array ($value) && ($value == array())) {
                return null;
            }
        }
        // INTEGER (0)
        if ($type >= self::INTEGER) {
            $type -= self::INTEGER;
            if (is_int ($value) && ($value == 0)) {
                return null;
            }
        }
        // BOOLEAN (false)
        if ($type >= self::BOOLEAN) {
            $type -= self::BOOLEAN;
            if (is_bool ($value) && ($value == false)) {
                return null;
            }
        }
        return $value;
    }

}
